Method of manufacturing organic EL device, and organic EL device

ABSTRACT

Grooves ( 3 R,  3 G,  3 B) corresponding to red, green and blue respectively are formed on a substrate ( 40 ), and the edge portion of each groove ( 3 R,  3 G,  3 B) is formed so as to be farther from a side of substrate ( 40 ) in order. The edge portion of each groove ( 3 R,  3 G,  3 B) is immersed in an organic EL solution ( 8 R,  8 G,  8 B) of corresponding color, the grooves ( 3 R,  3 G,  3 B) are severally filled with the organic EL solution ( 8 R,  8 G,  8 B) of corresponding color using capillary phenomenon, and thus a full-color organic EL display device is manufactured.

This is a continuation of PCT/JP01/07472, filed Aug. 30, 2001.

TECHNICAL FIELD

The present invention relates to a method of manufacturing an organic ELdevice and an organic EL device, more particularly to a method ofmanufacturing the organic EL device, by which organic EL elements areformed using capillary phenomenon, and an organic EL device.

BACKGROUND ART

An organic EL (Electroluminescence) display device has advantages thatit is easily manufactured in a thin plate state, has quick responsetime, and consumes less electricity due to no need of back light, whichis prospective as a display device that replaces a liquid crystaldisplay device and a CRT (Cathode Ray Tube).

Although one piece of film is able to constitute an organic EL layer(emitting layer) in a monochrome organic EL display device, it isnecessary to form organic EL layers corresponding to the three primarycolors of red (R), green (G) and blue (G) in each pixel in the case of afull-color organic EL display device. In the organic EL display deviceof 170 ppi (pixel per inch), for example, the size of one pixel is 150(m(150 (m and one pixel is constituted by three sub-pixels of which eachsize is 50 (m(150 (m. The three sub-pixels are a red sub-pixel, a greensub-pixel and a blue sub-pixel. Therefore, it is necessary to form eachof a red-emitting organic EL layer, a green-emitting organic EL layer,and a blue-emitting organic EL layer with the width of 50 (m.

In recent years, a high resolution display device having 200 ppi (pixelsize: 127 (m, sub-pixel width: 42.3 (m) to 500 ppi (pixel size: 50.8 (m,sub-pixel width: 17 (m) has been required. Further, various kinds ofscreen size from as small as approximately 2 inches to as large asapproximately 30 inches have been required.

The organic EL display device is manufactured by forming TFTs (thin filmtransistor), insulating films, electrodes, and organic EL layers on asubstrate called a mother glass. Even in the case of the organic ELdisplay device having a small screen size, a large substrate with thesize of approximately 400 m(500 mm to 730 mm(920 mm is used and aplurality of organic EL display devices are simultaneously manufacturedon one substrate in order to reduce manufacturing cost. In future, it isexpected that a larger substrate than up to now will be used due to thedemand of further reduction of the manufacturing cost and a largerscreen size.

In the case of low molecular organic EL material, the organic EL layersof three colors are formed in each pixel region by depositing theorganic EL material of red emission, green emission and blue emission onthe substrate using a shadow mask. However, in polymeric organic ELmaterial, heat decomposes polymer and thus it is impossible to form theorganic EL film by a deposition method. For this reason, in general, acoater capable of performing an inkjet method is generally used, and inkwhich is made of the organic EL material is sprayed in a dotted stateonto the substrate by each sub-pixel to form the organic EL layer.

In the coater for the inkjet method, it is necessary to spray aplurality of ink dots in one sub-pixel region. At this point, it isdifficult to form the organic EL layer uniformly in the entire sub-pixelregion because of overlapping of dots or the occurrence of gap betweendots. Consequently, although the coater for the inkjet method can beapplied for a display device having the sub-pixel size of approximately50 (m(150 (m, it may not be applicable for manufacturing a displaydevice of higher resolution.

Further, as the substrate size increases, it is expected that theposition of dots shift from a predetermined position due to the affectof thermal expansion of substrate.

Moreover, since the coater for the inkjet method sprays the organic ELmaterial onto all sub-pixels, it has a drawback that it takes more timein proportion to the number of sub-pixels and thus the manufacturingcost increases.

DISCLOSURE OF THE INVENTION

The object of the present invention is to provide a method ofmanufacturing an organic EL device and an organic EL device, whosemanufacturing is easier and the manufacturing cost is reduced comparingto a conventional method, and which is applicable for a high-resolutiondisplay device.

In the present invention, grooves are formed in the insulating film onthe substrate and the grooves are filled with a solution in which theorganic EL material is dissolved using capillary phenomenon.

For example, in forming the organic EL layer, the solution in which theorganic EL material is dissolved is prepared. Then, after the groovesare filled with the solution using capillary phenomenon, the solution isdried to form the organic EL layer in the grooves. Thus, the organic ELlayer having a uniform thickness is easily formed. To increase luminousefficiency of organic EL element, there are cases where a buffer layer(such as a hole transport layer and an electron transport layer) isformed between the electrode and the organic EL layer. By selecting asolution in which the material of the buffer layers are dissolved, thebuffer layers can be formed using capillary phenomenon as well similarto the organic EL layer.

Further, in the case of using organic electrodes, electrode layers canbe formed using capillary phenomenon similar to the organic EL layer byselecting a solution in which the electrode material is dissolved.

When forming a full-color organic EL display device, it is required toindividually form the red-emitting organic EL layer, the green-emittingorganic EL layer, and the blue-emitting organic EL layer. In the presentinvention, three sets of grooves are formed per one pixel and any one ofthe red-emitting organic EL layer, the green-emitting organic EL layer,and the blue-emitting organic EL layer is formed in each set of groovesby using capillary phenomenon. This makes it possible to easily form theorganic EL layer having each luminescence color in a uniform thickness,and thus to manufacture the full-color organic EL display device ofsuperior display quality at a low cost.

If the luminous efficiency of the red-emitting organic EL layer, thegreen-emitting organic EL layer, and the blue-emitting organic EL layeris not the same, adjusting the number or the width of grooves in eachset makes apparent luminescence intensity be the same.

Further, individually controlling the luminescence of the organic ELlayer of a same set (same luminescence color) in one pixel facilitatesgradation display (middle gradation display).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a circuit diagram showing an example of the organic EL deviceof the present invention.

FIG. 2 is a schematic cross-sectional view showing a structure exampleof the organic EL device of the present invention.

FIG. 3 is a schematic view showing the principle of the presentinvention.

FIG. 4 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (1).

FIG. 5 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (2).

FIG. 6 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (3).

FIG. 7 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (4).

FIG. 8 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (5).

FIG. 9 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (6).

FIG. 10 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (7).

FIG. 11 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (8).

FIG. 12 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (9).

FIG. 13 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (10).

FIG. 14 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (11).

FIG. 15 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (12).

FIG. 16 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (13).

FIG. 17 is a schematic view showing the method of manufacturing theorganic EL device of the first embodiment of the present invention (14).

FIG. 18 is a schematic view showing a substrate in which a large numberof grooves are formed for each luminescence color.

FIG. 19 is a schematic view showing the state where the substrate ismade perpendicular and immersed in a solution.

FIG. 20 is a schematic view showing the state where the substrate istilted and immersed in the solution.

FIG. 21 is a schematic cross-sectional view showing a structure exampleof the organic EL device where a buffer layer is provided between anelectrode and an organic EL layer.

FIG. 22 is a schematic view showing the method of manufacturing theorganic EL display device of the second embodiment in the presentinvention.

FIG. 23 is a schematic view showing an example where the number ofgrooves for blue sub-pixel is larger than the number of grooves for redand green sub-pixels.

FIG. 24 is a schematic view showing an example where the width ofgrooves for blue sub-pixel is wider than the width of grooves for redand green sub-pixels.

FIG. 25 is a view showing the method of manufacturing the organic ELdevice of the third embodiment of the present invention (1).

FIG. 26 is a view showing the method of manufacturing the organic ELdevice of the third embodiment of the present invention (2).

FIG. 27 is a view showing the method of manufacturing the organic ELdevice of the third embodiment of the present invention (3).

FIG. 28 is a view showing the method of manufacturing the organic ELdevice of the third embodiment of the present invention (4).

FIG. 29 is a view showing the method of manufacturing the organic ELdevice of the third embodiment of the present invention (5).

FIG. 30 is a view showing the method of manufacturing the organic ELdevice of the third embodiment of the present invention (6).

FIG. 31 is a view showing the method of manufacturing the organic ELdevice of the third embodiment of the present invention (7).

FIG. 32 is a view showing the method of manufacturing the organic ELdevice of the third embodiment of the present invention (8).

FIG. 33 is a view showing the method of manufacturing the organic ELdevice of the third embodiment of the present invention (9).

FIG. 34 is a view showing the method of manufacturing the organic ELdevice of the third embodiment of the present invention (10).

FIG. 35 is a view showing the method of manufacturing the organic ELdevice of the third embodiment of the present invention (11).

FIG. 36 is a view showing the method of manufacturing the organic ELdevice of the third embodiment of the present invention (12).

BEST MODE FOR CARRYING OUT THE INVENTION

The embodiments of the present invention will be described based on thedrawings as follows.

FIG. 1 is the circuit diagram showing an example of the organic ELdisplay device of active matrix type.

A plurality of data lines 41 and power supply lines 42, which extend invertical directions, and a plurality of scanning lines 43 extending inhorizontal directions are formed on a glass substrate 40. Regionssurrounded by the data lines 41, the power supply lines 42 and thescanning lines 43 are sub-pixel regions. In this embodiment, thesub-pixels of red emission, green emission and blue emission arearranged in due order in the horizontal directions, and the sub-pixelsof a same color are arranged in the vertical directions.

A TFT for switching 44, a TFT for driving 45, a capacitor 46 and anorganic EL element (light-emitting element) 47 are provided for eachsub-pixel region.

The gate, the source and the drain of the TFT for switching 44 arerespectively connected to the scanning line 43, the gate of the TFT fordriving 45, and the data line 41. Further, the TFT for driving 45 isconnected between the power supply line 42 and the anode of the organicEL element 47. Furthermore, the capacitor 46 is connected between thegate of the TFT for driving 45 and the power supply line 42.

In the organic EL display device of this configuration, when apredetermined voltage is supplied to each data line 41 and a scanningsignal is supplied only to the scanning line 43 of the first row, theTFTs for switching 44 connected to the scanning line 43 on the first roware turned on to accumulate the voltage of data line 41 in the capacitor46.

A current corresponding to the voltage flows from the power supply line42 to the organic EL element 47 via the TFT for driving 45, and eachorganic EL element 47 on the first row emits light. Subsequently, whenthe predetermine voltage is supplied to each data line 41 and thescanning signal is supplied only to the scanning line 43 on the secondrow, each organic EL element 47 on the second row emits light.

As described, by sequentially driving the organic EL elements on eachrow, a desired character or image can be displayed.

FIG. 2 is the schematic cross-sectional view showing the structure ofthe above-described organic EL display device of active matrix type.Note that the TFT for switching shown in FIG. 1 is not shown in FIG. 2.

An underlying insulating film 51 made of SiO₂ or another insulatingmaterial is formed on the glass substrate 40, and a polysilicon film 52that is an operating layer of TFT is selectively formed on theunderlying insulating film 51. A pair of highly concentrated impurityregions 52 a, which are the source/drain of TFT, are formed in thepolysilicon film 52, sandwiching a channel region.

A gate insulating film 53 made of SiO₂ or another insulating material isformed on the polysilicon film 52 and underlying insulating film 51.Further, the gate electrode 54 of TFT is formed on the gate insulatingfilm 53 in the area above the channel region of the polysilicon film 52.Then, an interlayer insulating film 55 made of SiO₂ or anotherinsulating material is formed on the gate electrode 54 and gateinsulating film 53.

Wiring 56 is formed on the interlayer insulating film 55 in apredetermined pattern. The predetermined wiring of the wiring 56 iselectrically connected to the highly concentrated impurity regions 52 aof TFT for driving via contact holes.

The wiring 56 is covered with an interlayer insulating film 57 made ofSiO₂ or another insulating material. An anode 58 made of ITO (Indium-TinOxide) is formed on the interlayer insulating film 57 in a predeterminedpattern. The anode 58 is electrically connected to one of the highlyconcentrated impurity regions 52 a (source) of TFT for driving via thecontact hole and wiring 56.

An insulating film 60 made of SiO₂ or another insulating material and aninsulating film 61 made of polyimide are laminated on the anode 58 andinterlayer insulating film 57. A groove 62 extending in the verticaldirections of the document of FIG. 2 is formed in the insulating films(60, 61).

An organic EL layer (emitting layer) 59 is formed on the anode 58 at thebottom of the groove 62. Although the anode 58 is individually formed byeach sub-pixel region, the organic EL layer 59 is formed across aplurality of sub-pixels arranged in the longitudinal direction of thegroove 62.

A cathode 63 made of an Al/Li (aluminum/lithium) alloy, for example, isformed on the insulating film 61 and the organic EL layer 59 inside thegroove 62. The anode 58, the organic EL layer 59 and the cathode 63constitute the organic EL element 47 shown in FIG. 1.

Note that one or more of the electron transport layer, the holetransport layer and a contact layer (layer for improving the contactproperty) may be arranged between the anode 58 and cathode 63 in orderto improve a luminous efficiency of the organic EL layer 59.Hereinafter, the electron transport layer, hole transport layer andcontact layer are referred to as a buffer layer.

In the organic EL display device of this configuration, when a voltageis supplied between the anode 58 and cathode 63, the organic EL layer 59emits light in a color (red, green or blue) corresponding to itsmaterial, and the light emits toward the substrate 40.

In the following, the principle of the method of manufacturing theorganic EL device in the present invention will be described. In thepresent invention, the edge of the groove formed on the substrate isimmersed in the solution in which the organic EL material is dissolved,and the groove is filled with the solution by capillary phenomenon toform the organic EL layer.

When the substrate, on which the grooves are formed, is made to standwhile its edge is immersed in liquid having property to wet thesubstrate material, capillary phenomenon allows the liquid to go up inthe grooves. The inventors of this application has once conductedresearch on manufacturing polyacetylene narrow wire by using an SiO₂substrate on which grooves were formed and Ziegler-Natta catalyst. Atthat time, the inventors confirmed that a toluene solution went up thegrooves by way of experiment, and presented the result in the followingthesis.

Nobuo Sasaki, Yoshihiro Takao, and Nagisa Ohsako, ‘Selective Growth ofPolyacetylene Narrow Wires Utilizing Capillary phenomenon of CatalystSolution in Grooves’, Japanese Journal of Applied Physics, Vol.31,pp.L741–L743(1992).

As shown in FIG. 3, when a groove 12 is formed on a substrate 11 and theedge of groove 12 is immersed in liquid 13 having property to wet thesubstrate 11, capillary phenomenon allows the liquid 13 to go up in thegroove 12. When, in FIG. 3, the substrate 11 is allowed to stand uprightto a liquid surface, the relationship shown in the following equation(1) holds supposing that the ingression distance (height of liquid goingup) of liquid 13 into the groove 12 is h, the density of liquid 13 is (,the surface tension of liquid 13 is (, gravitational acceleration is g,the width of groove 12 is w, the depth of groove 12 is d, and contactangle of liquid 13 to the substrate 11 is (.h(gw=((2d+w)cos(  (1)

For example, when the width w and the depth d of groove 12 are 0.5(m and0.5(m, respectively, the ingression distance (height) h of liquid 13 is17 m. Further, when the width w and the depth d of groove 12 are 3 (mand 1 (m, respectively, the ingression distance (height) h of liquid 13is 4.8 m.

Note that these are calculated values when the substrate 11 is SiO₂, theliquid 13 is toluene, the density ( of liquid 13 is 0.8669 g/cm³, thesurface tension ( of liquid 13 is 28.52 dyn/cm and the contact angle (of liquid 13 to the substrate 11 is 30 degrees.

It is to be noted that the following equation (2) holds when thesubstrate 11 is immersed in the liquid 13 tilting by angle (from anupright state.h(gw cos(=((2d+w)cos(  (2)

As it is clear from equation (2), the ingression distance h of liquid 13can be larger by tilting the substrate 11.

Next, the specific embodiments of the method of manufacturing theorganic EL device and the organic EL device in the present inventionwill be described.

(First Embodiment)

The full-color organic EL display device uses a red-emitting organic ELmaterial, a green-emitting organic EL material, and a blue-emittingorganic EL material. For example, the red-emitting organic EL materialis copoly(2,5-didodecyloxy-1,4-phenylenebutadiynylene)(3-dodecyloxycarbonylthienylenebutadiynylene). Further, the green-emitting organicEL material iscopoly(2,5-dialkoxy-p-phenylenebutadiynylene)(2-alkoxy-m-phenylenebutadiynylene).The blue-emitting organic EL material iscopoly((4,4′-biphenylylenelbutadiynylene)(4-dodecyloxy-m-phenylenebutadiynylene).

The embodiments of the present invention uses solutions where each ofthese organic EL materials is dissolved in toluene, and a band-shapedorganic EL layer is formed using capillary phenomenon. The concentrationof the organic EL material in the solution is 2% by weight, for example.

In the following, the method of manufacturing the organic EL device(display device) of the first embodiment will be described withreference to the cross-sectional view shown in FIG. 2 and the schematicdrawings shown in FIGS. 4 to 17. It is assumed that the TFTs, wiring 56,interlayer insulating film 55, 57, anode 58 and the like are formed onthe substrate 40 by a known deposition method and a knownphotolithography method (refer to FIG. 2).

After the anode 58 is formed on the interlayer insulating film 57 byITO, SiO₂ is deposited on the entire upper surface of the substrate 40to form the insulating film 60, and the insulating film 60 covers theanode 58. Subsequently, a groove for red sub-pixel 3R, a groove forgreen sub-pixel 3G and a groove for blue sub-pixel 3B are formed on theinsulating film 60 as shown in FIG. 4.

The three grooves (3R, 3G, 3B) are formed such that the distance of theedge of the groove for blue sub-pixel 3B is farthest from one side ofthe substrate 40 (the bottom side in FIG. 4), followed by the edge ofthe groove for green sub-pixel 3G and the edge of the groove for redsub-pixel 3R, which are closer to the side in this order. Although FIG.4 shows only one each of the grooves (3R, 3G, 3B) for simplifyingexplanation, a large number of grooves (3R, 3G, 3B) are actually formedon the substrate 40 as shown in FIG. 18.

Then, as shown in FIG. 5, stoppers (5 a, 5 b) are formed in the middleof the groove for red sub-pixel 3R and groove for green sub-pixel 3G toprevent the organic EL material from entering the grooves (3R, 3G). Thestopper 5 a is arranged at a farther position from one side of thesubstrate 40 than the stopper 5 b. The stoppers (5 a, 5 b) are made ofphotoresist and formed via selective exposure and development process.The both stoppers (5 a, 5 b) are formed on the substrate 40 outside adisplay region (region where sub-pixels are arranged).

Next, as shown in FIG. 6, there is prepared a container with a polymericorganic EL solution (hereinafter, referred to as a blue solution) 8Bthat becomes a blue emitting layer. Then, the edge of groove 3B isimmersed in the blue solution 8B while standing the substrate 40upright. Consequently, capillary phenomenon allows the blue solution 8Bto enter the groove 3B above the liquid surface and the entire groove 3Bis filled with the blue solution 8B.

At this time, the blue solution 8B enters the grooves (3R, 3B) as well,but the stoppers (5 a, 5 b) block the ingression of blue solution 8Babove the stoppers (5 a, 5 b).

Next, the substrate 40 is pulled out from the blue solution 8B, anddried to let toluene evaporate from the blue solution 8B in the grooves.As a result, a blue-emitting organic EL layer 6B is formed in the groove3B as shown in FIG. 7.

Subsequently, as shown in FIG. 8, a container with resist stripper 4 isprepared, and the substrate 40 is immersed in the resist stripper 4 to aposition where the stopper 5 b of the groove for green sub-pixel 3Gimmerses. Then, the substrate 40 is pulled out after the stopper 5 b isstripped off. Thus, the organic EL layer 6B under the liquid surface ofthe stripper 4 is removed as shown in FIG. 9.

Next, as shown in FIG. 10, there is prepared a container with apolymeric organic EL solution (hereinafter, referred to as a greensolution) 8G that becomes a green emitting layer. Then, the edge ofgroove 3G is immersed in the green solution 8G while standing thesubstrate 40 upright. Consequently, capillary phenomenon allows thegreen solution 8G to enter the groove 3G above the liquid surface andthe entire groove 3G is filled with the green solution 8G.

At this time, the green solution 8G does not enter the groove 3B sincethe edge of the groove for blue sub-pixel 3B is apart from the liquidsurface of green solution 8G. Further, since the stopper 5 a is providedfor the groove for red sub-pixel 3R, the green solution 8G enters thegroove 3R only to the position of stopper 5 a.

Next, the substrate 40 is pulled out from the green solution 8G, anddried to let toluene evaporate from the green solution 8G in thegrooves. As a result, a green-emitting organic EL layer 6G is formed inthe groove 3G as shown in FIG. 11.

Subsequently, as shown in FIG. 12, the substrate 40 is immersed uprightin the resist stripper 4 to the position where the stopper 5 a of thegroove for red sub-pixel 3R immerses and the stopper 5 a is removed.Thus, the green emitting layer 6G under the liquid surface is removed asshown in FIG. 13.

Next, as shown in FIG. 14, there is prepared a container with apolymeric organic EL solution (hereinafter, referred to as a redsolution) 8R that becomes a red emitting layer. Then, the edge of groove3R is immersed in the red solution 8R while standing the substrate 40upright. Consequently, capillary phenomenon allows the red solution 8Rto enter the groove 3R above the liquid surface and the entire groove 3Ris filled with the red solution 8R.

At this time, the red solution 8R does not enter the grooves (3B, 3G)since the edge of the groove for blue sub-pixel 3B and groove for greensub-pixel 3G is apart from the liquid surface of red solution 8R.

Next, the substrate 40 is pulled out from the red solution 8R in thecontainer, and dried to let toluene evaporate from the red solution 8Rin the grooves. As a result, a red emitting layer 6R is formed in thegroove 3R as shown in FIG. 15.

Thus, the edge of groove 3R is immersed in the resist stripper 4 toremove the red emitting layer 6R at the edge portion as shown in FIG.16.

As described above, the red emitting layer 6R, green emitting layer 6Gand blue emitting layer 6B are respectively formed in the grooves (3R,3G, 3B) as shown in FIG. 17.

After that, polyimide is coated on the entire surface to form theinsulating film 62, and grooves on which the organic EL layer 59 (6R,6G, 6B) is exposed are formed in the insulating film 62 (refer to FIG.2). Then, the Al/Li alloy is deposited on the entire surface by asputtering method, for example, to form the cathode 63. The organic ELdisplay device is manufactured in this manner.

According to this embodiment, the solution, in which the organic ELmaterial is dissolved, is allowed to enter the grooves using capillaryphenomenon to form the organic EL layer, so that the formation oforganic EL layer is quite easy and thus the manufacturing cost isreduced, whereas the organic EL layer of a uniform thickness can beformed. Furthermore, it can be applied for the high-resolution organicEL display device by adjusting the width of the grooves (3R, 3G, 3B).

Although description has been made in the above-described embodiment forthe example where the polymeric organic EL material was used as thematerial of organic EL layer, the present invention is not limited tothe polymeric organic EL material and it is possible to use the lowmolecular organic EL material as long as it is soluble in solvent.

In addition, in the above-described embodiment, the edge portions ofgrooves (3R, 3G, 3B) were immersed in the solution 8 while standing thesubstrate 40 upright to the liquid surface of the organic EL solution 8(8R, 8G, 8B) as shown in FIG. 19. However, the substrate 40 may beimmersed in the solution 8 with a slope as shown in FIG. 20. In thiscase, the distance of the solution 8 going up in the grooves bycapillary phenomenon is larger comparing to the case where the substrate40 is immersed upright in the solution 8.

Moreover, as described above, it is often the case where the bufferlayer such as the hole transport layer, electron transport layer andcontact layer is arranged.

FIG. 21 is the view showing the organic EL display device where a bufferlayer (hole transport layer) 64 made up of PEDT/PSS is provided betweenthe anode 58 and organic EL layer 59. This layer is formed by dissolvingPEDT/PSS in isopropyl alcohol and filling the grooves with it usingcapillary phenomenon in the same manner as the above-described formingmethod of organic EL layer.

Further, since the flow of current between organic EL layers can bedisregarded when the buffer layer is in high resistance, the bufferlayer is not formed for each organic EL element but may be commonlyformed for each organic EL element. In such a case, the anode 58 isformed on the interlayer insulating film 57, the buffer layer 64 andinsulating film 60 are further formed on the entire surface of thesubstrate 40, and then, the grooves are formed in the insulating film 60to form the organic EL layer using capillary phenomenon as describedabove.

Although the anode 58 is formed by ITO in the example shown in FIG. 21,it may be formed by conductive polymeric material instead of ITO. Inthis case, it is also possible to form the layer by filling the grooveswith a conductive polymeric material solution using capillary phenomenonsimilar to the above-described forming method of the organic EL layer.Highly conductive material is required as an electrode material, and theelectric conductivity of 30 to 200 S/cm is easily obtained whenpolyaniline is used for example. An N-methyl 1-2-pyrrolidone solutionhaving 0.5% by weight is used in order to fill the grooves withpolyaniline by capillary phenomenon.

Furthermore, although the groove 62 was linearly formed in theabove-described first embodiment, the groove 62 may be formed in a bentor curved shape.

Second Embodiment

FIG. 22 is the schematic view showing the method of manufacturing theorganic EL display device of the second embodiment in the presentinvention. Description will be made with reference to thecross-sectional view of FIG. 2 in this embodiment as well.

In this embodiment, after the anode 58 and the interlayer insulatingfilm 60 are formed similar to the first embodiment, a plurality ofgrooves (4 for each color in FIG. 22) are formed for one anode 58. Notethat the three grooves (3R, 3G, 3B) are formed such that the edge of thegrooves for red sub-pixel 3R is closest to one side of the substrate 40(the bottom side in FIG. 22), followed by the grooves for greensub-pixel 3G and the grooves for blue sub-pixel 3B, which become fartherfrom the side of substrate 40 in this order.

Then, the grooves for red sub-pixel 3R is filled with the red solution,the grooves for green sub-pixel 3G is filled with the green solution,the grooves for blue sub-pixel 3B is filled with the blue solutionsimilar to the first embodiment, and thus forming the red-emittingorganic EL layer 6R, green-emitting organic EL layer 6G andblue-emitting organic EL layer 6B.

Subsequently, the insulating film 61 is formed, the groove is formed inthe insulating film 61 to expose the organic EL layers (6R, 6G, 6B), andthen the cathode 63 made up of the Al/Li alloy is formed, similar to thefirst embodiment.

In addition to the same effects obtained in the first embodiment, thisembodiment exerts the effects shown below.

When the luminous efficiency of organic EL layer is different amongluminescence colors, the luminescence intensity of the red sub-pixel,green sub-pixel and blue sub-pixel is made to be uniform by adjustingthe number of grooves for each color. Generally, the luminous efficiencyof the blue organic EL layer is lower than that of the red organic ELlayer and green organic EL layer, so that the number of the grooves forred sub-pixel 3R and the grooves for green sub-pixel 3G are set to threeeach for one sub-pixel, the number of the grooves for blue sub-pixel 3Bis set to five for one sub-pixel, and thus the luminescence intensity ofeach sub-pixel can be uniformized.

Note that the width of the grooves for blue sub-pixel may be thickerthan that of the grooves for red sub-pixel 3R and the grooves for greensub-pixel 3G. Accordingly, it is also possible to uniformize theluminescence intensity of each sub-pixel.

(Modified Example)

When a plurality of organic EL layers are formed in one sub-pixelregion, as shown in FIG. 22, a plurality of TFTs for driving may beformed for one sub-pixel to allow each organic EL layer to emit lightindividually. Allowing a plurality of organic EL layers in one sub-pixelto individually emit light facilitates the display of middle gradation.

In other words, the organic EL display device of active matrix typeusually displays middle gradation by controlling the electric currentflowing in the TFTs for driving. However, in the case of controlling thecurrent flowing in the TFTs for driving to display middle gradation, thevariation of TFT characteristics could cause display unevenness. Asdescribed above, when a plurality of TFTs for driving are formed per onesub-pixel and gradation is displayed by individually controlling theluminescence of each organic EL layer, the occurrence of displayunevenness caused by the variation of TFT characteristics is prevented.Note that a plurality of grooves in one sub-pixel may be formed indifferent width from each other.

Furthermore, as described above, by forming a plurality of TFTs fordriving per one sub-pixel to individually control the luminescence ofeach organic EL layer, redundancy can be bestowed and the reduction ofproduction yield due to the disconnection of wire or the like can beprevented.

Third Embodiment

FIGS. 25 to 36 are the views showing the method of manufacturing theorganic EL display device of the third embodiment in the presentinvention. Description will be made with reference to thecross-sectional view of FIG. 2 in this embodiment as well.

In this embodiment, after the anode 58 and interlayer insulating film 60are formed on the substrate 40 similar to the first embodiment, thegroove for red sub-pixel 3R, groove for green sub-pixel 3G and groovefor blue sub-pixel 3B are formed as shown in FIG. 25. Although only oneeach of the grooves (3R, 3G, 3B) is shown in FIG. 25 to simplifyexplanation, a large number of the grooves (3R, 3G, 3B) are actuallyformed on the substrate 40.

At this time, the edge of the three grooves (3R, 3G, 3B) are arrangedsuch that the distance of the edge of the grooves for blue sub-pixel 3Bis farthest from one side of the substrate 40 (the bottom side in FIG.25), followed by the groove for green sub-pixel 3G and the groove forred sub-pixel 3R, which are closer to the side in this order.Additionally, the groove 3B is arranged such that the other end thereofis closer to the other side of the substrate 40 (the top side in FIG.25) than the other sides of the grooves (3R, 3G).

Subsequently, as shown in FIG. 26, the stopper 5 a is formed byphotoresist to prevent the organic EL solution from entering the groovefor red sub-pixel 3R.

Next, as shown in FIG. 27, there is prepared a container with thepolymeric organic EL solution (blue solution) 3G that becomes the greenemitting layer. Then, the edge of groove 3G is immersed in the greensolution 8G while standing the substrate 40 upright. Consequently,capillary phenomenon allows the green solution 8G to enter the groove 3Gabove the liquid surface and the entire groove 3G is filled with thegreen solution 8G.

At this time, since the edge of groove 3B is apart from the greensolution, the green solution 8G does not enter the groove 3B. Further,the green solution 8G enters the groove 3R to the position of stopper 5a. Next, the substrate 40 is pulled out from the green solution 8G, anddried to let toluene evaporate from the green solution 8G in thegrooves. As a result, a green-emitting organic EL layer 6G is formed inthe groove 3G as shown in FIG. 28.

Subsequently, as shown in FIG. 29, a container with the resist stripper4 is prepared, and the substrate 40 is immersed in the resist stripper 4to a position where the stopper 5 a of the groove for red sub-pixel 3Rimmerses. Then, the substrate 40 is pulled out after the stopper 5 a isstripped off. Thus, the organic EL layer 6G under the liquid surface ofthe stripper 4 is removed as shown in FIG. 30.

Next, as shown in FIG. 31, a container with the polymeric organic ELsolution (red solution) 8R that becomes the red emitting layer isprepared. Then, the edge of groove 3R is immersed in the red solution 8Rwhile standing the substrate 40 upright. Consequently, capillaryphenomenon allows the red solution 8R to enter the groove 3R above theliquid surface and the entire groove 3R is filled with the red solution8R.

At this time, since the edge of the groove for blue sub-pixel 3B and theedge of the groove for green sub-pixel 3G are apart from the redsolution 8R, the red solution 8R does not enter the grooves (3B, 3G).

Next, the substrate 40 is pulled out from the container, and dried tolet toluene evaporate from the red solution 8R in the groove. As aresult, a red-emitting organic EL layer 6R is formed in the groove 3R asshown in FIG. 32.

Subsequently, the edge of groove 3R is immersed in the resist stripper 4to remove the red emitting layer 6R in the edge portion as shown in FIG.33. FIG. 34 shows the state where the edge portion of red emitting layer6R in the groove 3R has been removed.

Next, as shown in FIG. 35, a container with the polymeric organic ELsolution (blue solution) 8B that becomes the blue emitting layer isprepared. Then, the edge of the other end of groove 3B is immersed inthe blue solution 8B while standing the substrate 40 upright.Consequently, capillary phenomenon allows the blue solution 8B to enterthe groove 3B above the liquid surface and the entire groove 3B isfilled with the blue solution 8B.

At this time, since the edge of the other sides of the groove for redsub-pixel 3R and the edge of the groove for green sub-pixel 3G are apartfrom the blue solution 8B, the blue solution 8B does not enter thegrooves (3R, 3G). Next, the substrate 40 is pulled out from the bluesolution, and dried to let toluene evaporate from the blue solution 8Bin the groove. As a result, a green-emitting organic EL layer 6B isformed in the groove 3B as shown in FIG. 36.

Subsequently, similar to the first embodiment, the insulating film 61 isformed and then the grooves are formed in the insulating film 61 toexpose the organic EL layers (6R, 6G, 6B). After that, the cathode 63 isformed by the Al/Li alloy.

The effects same as those of the first embodiment are also obtained inthis embodiment. Further, this embodiment has an advantage that thestopper 5 a may be formed only in the groove for red sub-pixel 3R andonly one stripping process to the stopper is required.

1. A method of manufacturing an organic EL device, comprising: formingfirst and second grooves in an insulating film on a substrate while thepositions of their one edge portions are shifted from each other;forming a stopper to prevent a solution from filling the length of saidfirst groove; immersing said one edge portions of said first and secondgrooves in a first solution in which a first organic EL material isdissolved, and filling said second groove with said first solution whilesaid stopper prevents said first solution from filling the length ofsaid first groove; removing said stopper; and immersing said one edgeportion of said first groove in a second solution in the state wheresaid second groove is apart from said second solution in which a secondorganic EL material is dissolved, and filling said first groove withsaid second solution.
 2. The method of claim 1, wherein the first andsecond grooves extend over two or more pixel sites.
 3. A method ofmanufacturing an organic EL device, comprising: forming first and secondgrooves extending over two or more pixel sites in an insulating film ona substrate while the positions of their one edge portions and the otheredge portions are shifted from each other; immersing said one edgeportion of said second groove in a first solution in the state wheresaid first groove is apart from said first solution in which a firstorganic EL material is dissolved, and filling said second groove withsaid first solution; and immersing said other edge portion of said firstgroove in a second solution in the state where said second groove isapart from said second solution in which a second organic EL material isdissolved, and filling said first groove with said second solution.
 4. Amethod of manufacturing an organic EL device, comprising: forming first,second and third grooves in an insulating film on a substrate while thepositions of their one edge portions are shifted from each other;forming first and second stoppers to prevent a solution from filling thelength of said first and second grooves; preparing a first solution inwhich an organic material of a first luminescence color is dissolved;immersing said other edge portions of said first, second and thirdgrooves in said first solution, and filling said third groove with saidfirst solution while said first and second stoppers prevent said firstsolution from filling the length of said first and second grooves;removing said second stopper; preparing a second solution in which anorganic material of a second luminescence color is dissolved; immersingsaid one edge portions of said first and second grooves in said secondsolution in the state where said third groove is apart from said secondsolution, and filling said second solution in said second groove whilesaid first stopper prevents said second solution from filling the lengthof said second groove; preparing a third solution in which an organic ELmaterial of a third luminescence color is dissolved; and immersing saidone edge portion of said first groove in said third solution in thestate where said second and third grooves are apart from said thirdsolution, and filling said third groove with said third solution.
 5. Themethod of manufacturing the organic EL device according to claim 4,wherein a plurality of said first, second and third grooves are formedfor one pixel.
 6. The method of manufacturing the organic EL deviceaccording to claim 5, wherein at least one of said first, second andthird grooves is formed in the different number from the number of theother grooves.
 7. The method of manufacturing the organic EL deviceaccording to claim 4, wherein at least one of said first, second andthird grooves is formed in a different width from the other grooves. 8.The method of manufacturing the organic EL device according to claim 4,wherein the first, second and third grooves extend over two or morepixel sites.
 9. A method of manufacturing an organic EL device,comprising: forming first, second and third grooves in an insulatingfilm on a substrate while the positions of their one edge portions areshifted from each other and the position of the other edge portion ofthe third groove is shifted from the edge portions of said first andsecond grooves; forming a stopper to prevent a solution from filling thelength of said first groove; preparing a first solution in which anorganic material of a first luminescence color is dissolved; immersingsaid one edge portions of said first and second grooves in the firstsolution in the state where said third groove is apart from said firstsolution, and filling said second groove with said first solution whilesaid stopper prevents said first solution from filling the length ofsaid first groove; removing said stopper; preparing a second solution inwhich an organic material of a second luminescence color is dissolved;immersing said one edge portion of said first groove in said secondsolution in the state where said second and third grooves are apart fromsaid second solution, and filling said first groove with said secondsolution; preparing a third solution in which an organic material of athird luminescence color is dissolved; and immersing said other edgeportion of said third groove in said third solution in the state wheresaid first and second grooves are apart from said third solution, andfilling said third groove said third solution.
 10. The method ofmanufacturing the organic EL device according to claim 9, wherein aplurality of said first, second and third grooves are formed for onepixel.
 11. The method of manufacturing the organic EL device accordingto claim 10, wherein at least one of said first, second and thirdgrooves is formed in the different number from the number of the othergrooves.
 12. The method of manufacturing the organic EL device accordingto claim 9, wherein at least one of said first, second and third groovesis formed in a different width from the other grooves.
 13. The method ofmanufacturing the organic EL device according to claim 9, wherein thefirst, second and third grooves extend over two or more pixel sites. 14.An organic EL device, comprising: a substrate; a first insulating filmformed on said substrate; a first electrode formed on said insulatingfilm; a second insulating film, which is formed on said insulating filmand in which grooves are extended over two or more pixel sites and areprovided on a position corresponding to said first electrode; an organicEL layer that is formed in said grooves and whose one surface iselectrically connected to said first electrode; and a second electrodeelectrically connected to the other surface of said organic EL layerwherein plural sets of said grooves are provided in one pixel region andthe luminescence colors of the organic EL layers formed in each set ofgrooves are different from each other.
 15. The organic EL deviceaccording to claim 14, wherein the number of grooves of at least one setof each set is larger than the number of grooves of the other sets. 16.The organic EL device according to claim 14, wherein the width of atleast one set of each set is wider than the width of the grooves of theother sets.
 17. The organic EL device according to claim 14, wherein abuffer layer is provided at least between said first electrode and saidorganic EL layer or between said organic EL layer and said secondelectrode.
 18. A method of manufacturing an organic EL device,comprising: forming grooves extending over two or more pixel sites in aninsulating film on a substrate; filling said grooves by capillaryphenomenon with a solution in which a material that becomes an electrodeis dissolved; and drying said solution.
 19. An organic EL device,comprising: a substrate; a first insulating film formed on saidsubstrate; a first electrode formed on said insulating film; a secondinsulating film, which is formed on said insulating film and in whichgrooves are provided on a position corresponding to said firstelectrode; an organic EL layer that is formed in said grooves and whoseone surface is electrically connected to said first electrode; and asecond electrode electrically connected to the other surface of saidorganic EL layer, wherein: plural sets of said grooves are provided inone pixel region; and the luminescence colors of the organic EL layersformed in each set of grooves are different from each other.
 20. Theorganic EL device according to claim 19, wherein the number of groovesof at least one set of each set is larger than the number of grooves ofthe other sets.
 21. The organic EL device according to claim 19, whereinthe width of at least one set of each set is wider than the width of thegrooves of the other sets.